1. Technical Field
The present invention relates to a protective cover structure, and more specifically to a protective cover structure for closing an opening for assembly work which is formed in a wall of a case housing electric components.
2. Related Art
An electric device has been known in which, for the purpose of dustproof, waterproof, or electromagnetic wave shielding, electric components are accommodated in a case in which a dustproof, waterproof, or electromagnetic wave shielding structure is formed. For example, JP-A-2011-124062 discloses an electric device in which a driving electric power is supplied from an inverter to a motor for driving an electric vehicle. The device has a structure in which an opening for assembly work (hereinafter, referred to as an assembly work opening) is disposed in an electromagnetic wave shield case housing, for example, an inverter, and a work of fastening conductor terminals of a connector connected to the motor, to circuit conductors of the inverter is performed through the assembly work opening by using bolts and the like.
Particularly, the assembly work opening for fastening the conductor terminals of a connector to the circuit conductors of the inverter is relatively largely formed in consideration of workability. In view of safety, the assembly work opening must be closed by an insulative protective cover after the work is completed. In the device disclosed in JP-A-2011-124062, an interlock portion is disposed in a protective cover, and, after the protective cover is fitted to the assembly work opening, the inverter is allowed to start to operate by function of the interlock portion.
However, JP-A-2011-124062 fails to disclose in detail the configuration of the interlock portion. For example, the interlock portion may be configured so that a short-circuit pin is disposed on the inner side of the protective cover, a fitting detecting connector is disposed on the side of the case while being opposed to the short-circuit pin, and, when the protective cover is fitted to the assembly work opening, a fitting detecting circuit is closed by the short-circuit pin of the protective cover. It may be contemplated to configure an interlock mechanism in which the closing operation of the fitting detecting circuit causes a fitting detection signal to be produced, and the fitting detection signal is supplied to an inverter controller to start the operation of the inverter.
The fitting detection signal is transmitted through signal wires to the inverter controller. When the inverter controller is disposed in the shield case for the inverter, for example, the signal wires are laid in the shield case to be connected to the fitting detecting circuit. In the case where the inverter controller is disposed outside of the shield case, however, the signal wires must be drawn out from (or drawn into) the shield case, and therefore a hole through which the signal wires are to be passed must be formed in the shield case. In this case, therefore, measures such as waterproofing and dustproofing must be taken in the hole for the signal wires.
It is an object of the invention to simplify a structure relating to a draw-out hole for signal wires which are used for detecting that a protective cover is fitted to an assembly work opening of a case housing electric components.